1. Field of the Invention
The present invention relates to method and apparatus for etching a semiconductor substrate and more particularly to a method and apparatus for etching a semiconductor substrate wherein etching fluid is moved across selected areas of the substrate by dynamic force.
2. Description of the Prior Art
U.S. Pat. No. 3,041,225 issued Jun. 26, 1932 to Emeis and entitled METHOD AND APPARATUS FOR SURFACE TREATMENT OF P-N JUNCTION SEMICONDUCTORS, describes a structure which utilizes centrifugal force for increasing the flow velocity of the etching liquid by rotating a wafer member during processing about an axis normal to the surface being etched. During rotation, the etching liquid, supplied in form of a free jet, is flung outwardly by centrifugal force.
A nozzle shaped tube is positioned above a rotating disc containing a wafer. An etching liquid is thereby directed onto the wafer. Centrifugal force is imposed upon the etching fluid by the rotation of the disc.
U.S. Pat. No. 3,597,289, issued Aug. 3, 1971 to Kohl et al and entitled METHOD OF ETCHING A SEMICONDUCTOR BODY, describes a structure wherein a wafer is etched by applying a stream of etching fluid from a nozzle while the wafer is rotated under the nozzle. The etching fluid does not flow due to centrifugal force in this structure.
U.S. Pat. No. 3,674,579, issued Jul. 4, 1972 to Clinehens et al entitled METHOD OF FORMING ELECTRICAL CONDUCTORS, relates to a method of forming electrical conductors to selected regions of a semiconductor wafer. An aluminum film of approximately 10,000 angstroms is evaporated upon a silicon dioxide insulative evaporation mask which has been formed on a silicon wafer. A conductor mask is formed upon selected areas of the aluminum film. The masked aluminum film is placed upon a spinner. Phosphoric acid is continuously poured near the center of the masked metal film. The masked aluminum film is spun for a period of approximately four minutes, to remove the portions of the aluminum film which are not coated by the conductor mask, in order to form electrical conductors in contact with selected regions of the silicon wafer.
U.S. Pat. No. 3,953,265, issued Apr. 27, 1976 to Hood entitled MENISCUS-CONTAINED METHOD OF HANDLING FLUIDS IN THE MANUFACTURE OF SEMICONDUCTOR WAFERS, relates to a method for reducing the consumption of etchants used in manufacturing semiconductor devices comprising the steps of supporting a semiconductor wafer, metering a predetermined volume of etchant onto the surface of said wafer to form a meniscus-contained body of etchant thereon, maintaining said wafer static during etching, sensing the completion of said etching, and spinning said wafer upon completion of the etching to remove the etchant from the wafer and terminate the etching operation.
U.S. Pat. No. 4,339,297, issued Jul. 13, 1982 to Aigo entitled APPARATUS FOR ETCHING OF OXIDE FILM ON SEMICONDUCTOR WAFER, discloses an apparatus for applying photo-etching on one surface of a semiconductor wafer formed with oxide film is provided, which comprises a cup-shaped basin having at the bottom thereof a vertical passage for introducing etching liquid, and a chuck rotatably supported above said basin for vacuum-absorbing a semiconductor wafer at the bottom surface thereof, said one surface of wafer facing downward being contacted with etching liquid that is blown up vertically through said vertical passage of the basin, to thereby prevent the upward facing rear surface of wafer from being contacted with etching liquid to hold oxide film thereon, and means for rotating said chuck to remove any reaction gas resulted on said one surface of wafer.
U.S. Pat. No. 4,544,446, issued Oct. 1, 1985 to Cady entitled VLSI CHEMICAL REACTOR, discloses a VLSI chemical reactor that includes a fluid flow guide spaced from the corresponding substrate in the form of a wafer for significantly reducing contamination in the processing of semiconductor wafers. Processing chemicals are introduced in a continuous process through a central tube and through the fluid flow guide which is substantially planar and which is parallel to the surface of the wafer. A predetermined gap is maintained between the guide and the wafer such that fluid is maintained in the gap at all times critical in the processing of the wafer.